The hypothesis that the N-acetyltransferases (NAT) and deacetylases might play a determinate role in susceptibility to bladder cancer will be examined. Towards this goal, we will determine first whether there is any correlation between in vivo acetylation phenotyping and that of cellular levels of NAT or deacetylases in human urothelium cultures in vitro. Secondly, we will compare the relative distribution of acetylator phenotype among active smokers who have bladder cancer versus those smokers who do not manifest the disease. The in vivo phenotype determinations will be made by measurement of the urinary metabolites 5-acetylamino-6-formylamino-3-methyluracil and 1-methylxanthine following administration of caffeine.